1. Field of the invention
This invention relates to a waterproof connector used for a wire harness in an automobile. More specifically, the invention relates to a waterproof connector including a connector housing which ensures a waterproof function of a rubber plug attached to a covered wire even if any one of predetermined covered wires of different diameters is connected to a predetermined connection terminal.
2. Related art
In many cases, connectors, used for a wire harness in an automobile, are required to have a waterproof function. In such a connector, when a connection terminal with a wire is inserted into a connector housing (hereinafter referred to merely as "housing"), a rubber plug, fitted on an end portion of the wire, forms a seal relative to the exterior.
An example of a construction including a pair of waterproof connectors respectively having female and male terminals will now be described with reference to FIG. 5.
As shown in FIG. 5, the male terminal 2 has a centerline 2A extending through the center of the cross-sectional area of a male tab 2D, formed at a front end thereof, to a wire holder portion 2E formed at a rear end thereof. It is preferred that a centerline of a covered wire 5, compressively clamped by the wire holder portion 2E of the male terminal 2, either be aligned with the centerline 2A of the terminal or extend in the vicinity of this terminal centerline 2A. However, since the diameter of the covered wire 5 is larger than the thickness of the male tab 2D, they are not aligned with each other, and therefore it is necessary to make an adjustment by the wire holder portion 2E. A slanting portion or stepped portion 2B is provided for the purpose of this adjustment. As a result of the provision of this slanting portion 2B, a surface 2C of a base plate of the wire holder portion 2E is projected to a level below the male tab 2D. With this arrangement, the centerline of the covered wire 5 is either accurately or generally aligned with the centerline 2A of the terminal. Therefore, the male terminal 2 can be quite easily inserted into a female housing 20.
Then, a rubber plug 4, having a passage hole, is fitted on the front end portion of the covered wire 5. Then, the male terminal 2, having the rubber plug 4 fitted thereon, is inserted into the female housing 20. As a result, the male tab 2D is projected from a partition wall provided at a front portion of the female housing 20. At this time, the rubber plug 4 is press-fitted in a cavity 21 provided at a rear portion of the female housing 20. The outer diameter of the rubber plug 4 is larger than the diameter of the cavity, and upon press-fitting, an outer peripheral portion of the rubber plug is compressed. This compressed outer peripheral portion, that is, a sealing portion seals the cavity 21 relative to the exterior.
A male housing 11, having a female terminal 12 fitted therein, is fitted in the female housing 20, having the male terminal 2 fitted therein in this sealed condition, from the front side of this female housing. At this time, the male terminal 2 is fitted in the female terminal 12 to make an electrical connection therebetween. Incidentally, the female terminal 12, as in the male terminal 2, is sealed within the male housing 11 by a rubber plug 13 fitted on a front end of a covered wire 15 connected to the female terminal 12.
As described above, the specified covered wire is used according to its intended place and purpose, and predetermined connection terminal and housing are selected and used. Namely, one or few kinds of connection terminals, as well as one or few kinds of housings, could be used relative to the specified covered wire.
Therefore, when trying to use any one of a plurality of kinds of covered wires relative to one kind of connection terminal, problems arise with the strength of the connection terminal relative to the covered wire, as well as a retaining structure within the housing.
As described above, in the housing 20 of the above construction, from the viewpoints of the terminal inserting operation and the sealing ability of the rubber plug, the centerline 4C of the rubber plug and the centerline 21B of the cavity should preferably be aligned either accurately or generally.
However, in the case where a plurality of covered wires 5 of different outer diameters are compatible with the common male terminal 2, a problem arises with the wire holder portion 2E. For example, assuming that the height of clamping (hereinafter referred to as "clamping height") of the covered wire with an average outer diameter is a reference height, the clamping height of the covered wire with a larger diameter is larger, and also the clamping height of the covered wire with a smaller diameter is smaller.
When a covered wire 5C of the reference diameter is clamped by the male terminal 2 as shown in FIG. 6, the rubber plug 4 through which the covered wire 5C passes has a rubber plug centerline 22, and the cavity 21 at the rear portion of the housing 20 has a cavity centerline 23. At this time, the rubber plug centerline 22 is aligned with the cavity centerline 23. In the drawings, a sealing portion on the upper side of the centerline of the covered wire 5C is designated by w5 while a sealing portion on the lower side is designated by w6.
As shown in FIG. 7, a sealing portion w is uniformly formed between the outer periphery 26A of the rubber plug in a non-compressed condition (non-fitted condition) and the outer periphery 26B of the rubber plug in a compressed condition (fitted condition) over the entire periphery. In this case, the outer periphery 26B of the rubber plug in the compressed condition (fitted condition) is equal to an inner periphery 21A (FIG. 6) of the cavity.
A problem arises when a covered wire 5B larger in diameter than the covered wire 5C of the reference diameter is clamped as shown in FIG. 8. In this case, the covered wire 5B of a larger diameter is connected and held, using the male terminal 2 and the housing 20 which have the same sizes and shapes, respectively, as described above. Therefore, since the position of the base plate surface 2C is not changed, the position of the male terminal 2 within the housing 20 is not changed.
On the other hand, since the covered wire 5B has a larger diameter, the clamp height is larger when this wire is placed on the base plate surface 2C, and the centerline of the covered wire 5B of a larger diameter is shifted upwardly, and also the centerline 24 of the rubber plug through which the wire passes is also shifted upwardly. Namely, the centerline 24 of the rubber plug is not aligned with the centerline 25 of the cavity.
In this condition, when the male terminal 2 is inserted into the housing 20 as shown in FIG. 9, the sealing portion w at the outer peripheral portion of the rubber plug 4 is large at an upper portion whereas the sealing portion is hardly provided at a lower portion. Namely, with respect to the sealing portion w between the outer periphery 26A of the rubber plug in the non-compressed condition and the outer periphery 26B of the rubber plug in the compressed condition (fitted condition), the upper sealing portion w5 is large whereas the lower sealing portion w6 is hardly provided, thus causing an uneven condition. In an extreme case, there is a fear that a gap 27 may be formed between the lower end of the rubber plug 4 and the inner periphery 21A of the cavity. In such a condition, it is difficult to ensure a good waterproof ability.